If you specify both tag keys and tag values in the same request, Amazon Redshift returns
all security groups that match any combination of the specified keys and values. For
example, if you have owner and environment for tag keys,
and admin and test for tag values, all security groups that
have any combination of those values are returned.

If both tag keys and values are omitted from the request, security groups are returned
regardless of whether they have tag keys or values associated with them.